<?php
# MantisBT - A PHP based bugtracking system

# MantisBT is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 2 of the License, or
# (at your option) any later version.
#
# MantisBT is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with MantisBT.  If not, see <http://www.gnu.org/licenses/>.

/**
 * URL API
 *
 * Provides means for simplifying remote URL operations.
 *
 * @package CoreAPI
 * @subpackage URLAPI
 * @copyright Copyright 2000 - 2002  Kenzaburo Ito - kenito@300baud.org
 * @copyright Copyright 2002  MantisBT Team - mantisbt-dev@lists.sourceforge.net
 * @link http://www.mantisbt.org
 */

/**
 * Retrieve the contents of a remote URL.
 * First tries using built-in PHP modules (OpenSSL and cURL), then attempts
 * system call as last resort.
 * @param string $p_url The URL to fetch.
 * @return null|string URL contents (NULL in case of errors)
 */
function url_get($p_url)
{
    # Generic PHP call
    if (ini_get_bool('allow_url_fopen')) {
        $t_data = @file_get_contents($p_url);

        if ($t_data !== false) {
            return $t_data;
        }
        # If the call failed (e.g. due to lack of https wrapper)
        # we fall through to attempt retrieving URL with another method
    }

    # Use the PHP cURL extension
    if (function_exists('curl_init')) {
        $t_curl = curl_init($p_url);

        # cURL options
        $t_curl_opt[CURLOPT_RETURNTRANSFER] = true;

        # @todo It may be useful to provide users a way to define additional
        # custom options for curl module, e.g. proxy settings and authentication.
        # This could be stored in a global config option.

        # Default User Agent (Mantis version + php curl extension version)
        $t_vers = curl_version();
        $t_curl_opt[CURLOPT_USERAGENT] =
            'mantisbt/' . MANTIS_VERSION . ' php-curl/' . $t_vers['version'];

        # Set the options
        curl_setopt_array($t_curl, $t_curl_opt);

        # Retrieve data
        $t_data = curl_exec($t_curl);
        curl_close($t_curl);

        if ($t_data !== false) {
            return $t_data;
        }
    }

    # Last resort system call
    $t_url = escapeshellarg($p_url);
    return shell_exec('curl ' . $t_url);
}
